How do I calculate the share for partial ownership?

The calculation is made by multiplying all factors by the ownership share as a decimal. The ownership share is recorded in the Escritura (notarial deed). Typical distributions: 50/50 for married couples, 33.33/33.33/33.33 for three owners, or any other split. Example: cadastral value €300,000, ownership share 33.33%, imputation rate 1.1%, EU/EEA resident, full year. Pro-rata cadastral value: €300,000 × 33.33% = €99,990. Tax base: €99,990 × 1.1% = €1,099.89. Tax: €1,099.89 × 19% = €208.98. Each co-owner generally files a separate declaration and pays only their share. With mixed use, two declarations per owner. Important: calculate from the outset with the pro-rata cadastral value rather than computing the total and dividing afterwards — the result is the same, but the AEAT expects the pro-rata calculation per owner.